<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .con {
            width: 220px;
            height: 300px;
            border: 1px solid black;
            display: flex;
        }

        .con div {
            flex: 1;
        }
    </style>
</head>

<body>
    <div class="con">
        <div style="background-color:coral;">红色</div>
        <div style="background-color:lightblue;">蓝色</div>
        <div style="background-color:lightgreen;">带有更多内容的绿色 div</div>
    </div>
</body>

</html>